1. Field of the Invention
This invention relates generally to the processing of video images and, more particularly, to the processing of digitized video signals under the control of a data processing system.
2. Description of the Related Art
As the sophistication of the general population with respect to visual materials has increased, the need to have available relatively extensive image processing capabiliities has increased. For example, the weatherman in front of an apparently full-sized and frequently changing weather map has become so common as to be unremarkable even for the local broadcasting station.
The apparatus for processing video images, especially for processing images in real time, until the present invention, have generally occupied two extremes in image processing capability. On the one extreme, the apparatus has such limited capability as to be of modest use to the broadcasting station in other simple image processing applications. On the other extreme, the apparatus can be of such sophistication that the image processing capabilities are extremely broad. This latter extreme provides all the capability that is required in any typical image environment. However, the capability is achieved by having a data processing unit retrieve and manipulate each image point (generally referred to as a pixel) individually. The amount of data processing system resources that must be dedicated to process an image on a pixel by pixel basis is sufficiently large that the data processing system can be too expensive to be practical for many applications requiring video image processing capability. (For the typical video image format, the image is generally represented by a matrix of 512.times.512 image pixels, each image pixel being updated approximately 30 times each second. In addition, each image pixel is generally represented by at least four quantities, three color parameters and and an intensity parameter.) Along with the specialized programs needed to execute the video processing functions, a dedicated data processing system is frequently required. To accommodate the specialized nature of the image processing operations, a specialized data processing architecture may also be utilized.
A need has therefore been felt for video image processing apparatus that can provide flexibility for processing of images in real time under control of a data processing system, while minimizing the impact of the video image processing on the data processing system resources.